Methods and apparatus for endovascular heart valve replacement comprising tissue grasping elements

ABSTRACT

A method for endovascularly replacing a patient&#39;s heart valve including the following steps: endovascularly delivering an anchor and a replacement valve supported within the anchor to a vicinity of the heart valve in a collapsed delivery configuration, the anchor having grasping elements adapted to grasp tissue in a vicinity of the heart valve; expanding the anchor, thereby rotating the grasping elements; and grasping the tissue with the rotating grasping elements.

CROSS-REFERENCE

This application is a continuation application of U.S. application Ser.No. 13/282,247, filed Oct. 26, 2011, which is a continuation applicationof U.S. application Ser. No. 11/232,441, filed Sep. 20, 2005, now U.S.Pat. No. 8,828,078, which is a continuation-in-part application of U.S.application Ser. No. 10/972,287, filed Oct. 21, 2004, now U.S. Pat. No.7,748,389, which is a continuation-in-part of U.S. application Ser. No.10/746,240, filed Dec. 23, 2003, which is abandoned, all of which areincorporated herein by reference in their entireties and to whichapplications we claim priority under 35 USC .sctn.120.

BACKGROUND OF THE INVENTION

The present invention relates to methods and apparatus forendovascularly replacing a heart valve. More particularly, the presentinvention relates to methods and apparatus for endovascularly replacinga heart valve with a replacement valve using an expandable anchor andtissue grasping elements.

Heart valve surgery is used to repair or replace diseased heart valves.Valve surgery is an open-heart procedure conducted under generalanesthesia. An incision is made through the patient's sternum(sternotomy), and the patient's heart is stopped while blood flow isrerouted through a heart-lung bypass machine.

Valve replacement may be indicated when there is a narrowing of thenative heart valve, commonly referred to as stenosis, or when the nativevalve leaks or regurgitates. When replacing the valve, the native valveis excised and replaced with either a biologic or a mechanical valve.Mechanical valves require lifelong anticoagulant medication to preventblood clot formation, and clicking of the valve often may be heardthrough the chest. Biologic tissue valves typically do not require suchmedication. Tissue valves may be obtained from cadavers or may beporcine or bovine, and are commonly attached to synthetic rings that aresecured to the patient's heart.

Valve replacement surgery is a highly invasive operation withsignificant concomitant risk. Risks include bleeding, infection, stroke,heart attack, arrhythmia, renal failure, adverse reactions to theanesthesia medications, as well as sudden death. 2-5% of patients dieduring surgery.

Post-surgery, patients temporarily may be confused due to emboli andother factors associated with the heart-lung machine. The first 2-3 daysfollowing surgery are spent in an intensive care unit where heartfunctions can be closely monitored. The average hospital stay is between1 to 2 weeks, with several more weeks to months required for completerecovery.

In recent years, advancements in minimally invasive surgery andinterventional cardiology have encouraged some investigators to pursuepercutaneous replacement of the aortic heart valve. However, the currentdevices suffer from several drawbacks.

First, many of the devices available today can become mispositioned withrespect to the native valve. This misposition may arise for a number ofreasons, such as: the valve slipping after placement, improper initialpositioning arising from the difficulties associated with visualizingthe relative positions of the native and prosthetic valve, thedifficulty in transmitting tactile feedback to the user through thedelivery tool. This is a critical drawback because improper positioningtoo far up towards the aorta risks blocking the coronary ostia of thepatient. Furthermore, a misplaced stent/valve in the other direction(away from the aorta, closer to the ventricle) will impinge on themitral apparatus and eventually wear through the leaflet as the leafletcontinuously rubs against the edge of the stent/valve.

Moreover, some stent/valve devices simply crush the native valveleaflets against the heart wall and do not grasp or engage the leafletsin a manner that would provide positive registration of the devicerelative to the native position of the valve. This increases animmediate risk of blocking the coronary ostia, as well as a longer-termrisk of migration of the device post-implantation.

Another drawback of the devices known today is that during implantationthey may still require the patient to be on life support as the valvedoes not function for a portion of the procedure. This furthercomplicates the implantation procedure.

In view of drawbacks associated with previously known techniques forendovascularly replacing a heart valve, it would be desirable to providemethods and apparatus that overcome those drawbacks.

SUMMARY OF THE INVENTION

One aspect of the invention provides an apparatus for endovascularlyreplacing a patient's heart valve. The apparatus includes: an expandableanchor supporting a replacement valve, the anchor and replacement valvebeing adapted for percutaneous delivery and deployment to replace thepatient's heart valve. The anchor comprises a braid having graspingelements adapted to grasp tissue in a vicinity of the patient's heartvalve. The grasping elements preferably are atraumatic.

Another aspect of the invention provides an apparatus for endovascularlyreplacing a patient's heart valve, including: an expandable anchorsupporting a replacement valve, the anchor and replacement valve beingadapted for percutaneous delivery and deployment to replace thepatient's heart valve, the anchor comprising grasping elements adaptedto grasp tissue in a vicinity of the patient's heart valve. The anchoris self-expanding and has a delivery configuration, an at-restconfiguration and a deployed configuration, the at-rest configurationhaving a diameter larger than a diameter of the delivery configurationand smaller than a diameter of the deployed configuration. The graspingelements are positioned substantially parallel with the anchor in thedelivery configuration, at a first angle with the anchor in the at-restconfiguration and at a second angle with the anchor in the deployedconfiguration.

Yet another aspect of the invention provides a method for endovascularlyreplacing a patient's heart valve, the method including: endovascularlydelivering an anchor and a replacement valve supported within the anchorto a vicinity of the heart valve in a collapsed delivery configuration,the anchor comprising grasping elements adapted to grasp tissue in avicinity of the heart valve; expanding the anchor, thereby rotating thegrasping elements; and grasping the tissue with the rotating graspingelements.

In some embodiments, the tissue comprises leaflets of the patient'sheart valve. When the grasping elements grasp the leaflets, the anchoris substantially distal to the coronary ostia of the patient. Moreover,once grasped, the grasping elements prevent the distal movement of theanchor. In some embodiments, the grasping elements are integral with theanchor or part of the anchor. In other embodiments, the graspingelements are attached to the proximal region of the anchor.

In some embodiments the tissue comprises an annulus of the patient'sheart valve. When the grasping elements grasp the annulus, the anchor issubstantially proximal of the mitral apparatus. Moreover, once grasped,the grasping elements prevent the proximal movement of the anchor. Insome embodiments, the grasping elements are integral with the anchor orpart of the anchor. In other embodiments, the grasping elements areattached to the distal region of the anchor.

In any of the embodiments described herein, the grasping elements or thestep of grasping the tissue may provide a locating function for properlyplacing the apparatus. This locating function may be accomplishedwithout necessitating a precise placement of the replacement valve,especially in embodiments that comprise both proximal and distalgrasping elements, e.g., that grasp both the valve leaflets and thevalve annulus. This locating function advantageously may be accomplishedwithout necessitating tactile feedback regarding the positioning of thereplacement valve.

Additionally, in any of the embodiments described herein, the anchor maybe adapted for active expansion during deployment. Active expansion canoccur by actuating proximal and/or distal actuation elements of theanchor. The anchor may be configured for locking and may include alocking element. The replacement valve is situated within the anchor andis adapted to permit blood flow and prevent blood backflow both duringand after deployment.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIGS. 1A and 1B are schematic views of an anchor and valve apparatus inaccordance with the present invention. FIG. 1A illustrates the apparatusin a collapsed delivery configuration within a delivery system. FIG. 1Billustrates the apparatus in an expanded configuration partiallydeployed from the delivery system.

FIG. 2 illustrates an anchor of FIG. 1 in the collapsed deliveryconfiguration with locking elements separated.

FIG. 3 illustrates a braided anchor of the present invention with closedend turns Tu.

FIGS. 4A-4O are schematic detail views illustrating exemplary end turnsfor a braided anchor.

FIGS. 5A-5E illustrate additional features for end turns of a braidedanchor.

FIGS. 6A-6F illustrate deployment of an anchor with leaflet engagementelements on the deployment system.

FIG. 7 illustrates a deployed anchor with leaflet engagement elements onthe proximal end of the anchor.

FIGS. 8A-8C illustrate deployment of an anchor with anchor registrationor leaflet engagement elements and a seal.

FIGS. 9A-9B illustrate an embodiment of the apparatus with a seal thatdoes not reach the proximal end of the anchor during both systole anddiastole.

FIGS. 10A-10B illustrate an embodiment of the apparatus with a seal thatreaches the proximal end of the anchor during both systole and diastole.

FIGS. 11A-11D are schematic side views of various braided anchorconfigurations.

FIGS. 12A-12E are schematic side views of a deployment process for ananchor braid.

FIGS. 13A-13E are schematic views of different weave configurations foran anchor braid.

FIGS. 14A-14C illustrate an embodiment of a replacement heart valve andanchor in the undeployed and deployed configurations.

FIGS. 15A-15D illustrate an embodiment of a replacement heart valve andanchor having tissue grasping elements that rotate about the anchorduring active expansion of the anchor.

FIG. 16 is a cross-sectional view illustrating the apparatus of FIG. 15deployed across a patient's native valve.

FIGS. 17A and 17B illustrate variations of the apparatus of FIG. 15comprising alternative grasping elements deployed across a patient'snative valve.

FIGS. 18A-18C illustrate additional variations of the grasping elements.

FIGS. 19A and 19B illustrate a variation of the grasping elements thatapplies an outwardly-directed force, which can accommodate enlargementin a patient's native valve structures over time.

FIGS. 20A-20E illustrate deployment and resheathing of a replacementvalve and anchor having grasping elements via a delivery system.

FIG. 21 illustrates a seal for use with grasping elements coupled to ananchor.

FIG. 22 illustrates an alternative embodiment of the grasping elementsand seals of FIG. 21.

FIG. 23 illustrates another alternative embodiment of the graspingelements and seal of FIG. 21.

FIG. 24 illustrates the apparatus of FIG. 23 deployed across a patient'snative valve.

FIG. 25 illustrates alternative grasping elements that are attached tothe anchor.

FIGS. 26A-26B illustrate a variation of the attached grasping elementsof FIG. 25.

FIGS. 27A-27B illustrate additional, alternative attached graspingelements.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an apparatus and methods forendovascularly delivering and deploying an aortic prosthesis within apatient's native heart valve, referred to hereinafter as “replacing” apatient's heart valve. The delivery system includes a sheath assembly, amulti-lumen shaft, and a guide wire for placing the apparatusendovascularly within a patient and a user control allowing manipulationof the aortic prosthesis. The apparatus includes an anchor and areplacement valve. The anchor and the replacement valve are adapted forpercutaneous delivery and deployment within a patient's heart valve.

In some embodiments, the apparatus includes engagement elements and/or aseal inverting element situated along a proximal region of the anchor.The engagement elements are adapted to engage the native leaflets of thepatient's heart, or more preferably the proximal edge and/or thecommissural attachments of the native leaflets. The engagement elementsneed not extend all the way into the pocket or the distal end of thenative leaflet. The apparatus additionally or alternatively may compriseengagement elements along a distal region of the anchor for engaging anannulus of the native valve. The engagement elements may be formedintegrally with the anchor or may be attached to the anchor.

In some embodiments, the proximal and/or distal engagement elementscomprise grasping elements configured to grasp tissue in the vicinity ofthe patient's heart valve, e.g. to rotate into the tissue and secure theapparatus relative to the tissue. The grasping elements preferably areatraumatic. Preferred embodiments of the apparatus are depicted in FIGS.1-27, which are discussed in more detail below.

FIGS. 1A and 1B illustrate one embodiment of a delivery system and theapparatus of the present invention.

As illustrated by FIG. 1A, apparatus 10 comprising replacement valve 20and anchor 30 may be collapsed for delivery within a delivery system100. Delivery system 100 includes a guidewire 102, a nose cone 104,anchor actuation elements 106 (e.g., “fingers”) coupled to a multi-lumenshaft 108, an external sheath 110 having a proximal handle 111, and acontrol handle 120. Delivery system 100 further comprises distal regioncontrol elements (not shown) comprised of, or actuated by, control wires(not shown), which pass through one or more lumens of shaft 108 and arereversibly coupled to posts 32 of anchor 30 for manipulating a distalregion of apparatus 10. Thus, the distal region control elements mayfunction as a distal actuation element. The control wires may comprise,for example, strands of suture, or metal or polymer wires.

The delivery system also comprises proximal region control elements thatare comprised of, or actuated by, additional control wires that passthrough one or more lumens of shaft 108 and anchor actuation elements106. The wires reversibly couple the anchor actuation elements to aproximal region of anchor 30. In some embodiments, the anchor actuationelements and associated wires may be referred to as proximal actuationelements.

Control handle 120 is coupled to multi-lumen shaft 108. A knob 122disposed in slot 123 is coupled to the distal region control wires forcontrolling movement of the distal region of apparatus 10. Likewise, aknob 124 disposed in slot 125 is coupled to the proximal region controlwires for control of the proximal region of apparatus 10. Handle 120 mayalso have a knob 126 for, e.g., decoupling the proximal and/or distalregion control wires from apparatus 10, or for performing other controlfunctions.

As illustrated by FIG. 1B, apparatus 10 comprises an anchor 30 and areplacement valve 20. Anchor 30 preferably comprises a braid. Such braidcan have closed ends at either or both of its ends but preferably atleast in its proximal end. Replacement valve 20 is preferably coupled tothe anchor at posts 32 attached at a distal region of the anchor. Thus,posts 32 may function as a valve support and may be adapted to supportthe replacement valve within the anchor. In the embodiment shown, thereare three posts, corresponding to the valve's three commissureattachments. The posts can be attached to the braid of anchor 30. Theposts can be attached to the braid's distal region, as shown in FIG. 2,central region, or proximal region. Replacement valve 20 can be composedof a metal, a synthetic material and/or may be derived from animaltissue. Replacement valve 20 is preferably configured to be securedwithin anchor 30.

In preferred embodiments, anchor 30 is collapsible and/or expandable andis formed from material such as Nitinol™, cobalt-chromium steel orstainless steel wire. More preferably, an anchor 30 is self-collapsingand/or self-expanding and is made out of shape memory material, such asNitinol™. An anchor composed of shape memory material may self-expand toor toward its “at-rest” configuration. This “at rest” configuration ofan anchor can be, for example its expanded configuration, its collapsedconfiguration, or a partially expanded configuration (between thecollapsed configuration and the expanded configuration). In someembodiments, an anchor's at-rest configuration is between its collapsedconfiguration and its expanded configuration. Depending on the “at rest”diameter of the anchor and the diameter of the patient's anatomy at thechosen deployment location, the anchor may or may not self-expand tocome into contact with the diameter of the patient's anatomy at thatlocation.

Anchor 30 may be expanded to a fully deployed configuration from apartial deployed configuration (e.g., self-expanded or at-restconfiguration) by actively expanding, e.g., actively foreshortening,anchor 30 during endovascular deployment. Active foreshortening isdescribed in more detail in U.S. patent application Ser. No. 10/746,280,which is incorporated herein by reference in its entirety. During activeforeshortening, the distal region of anchor 30 may be pulled proximallyvia a proximally directed force applied to posts 32 via a distaldeployment system interface comprised of the distal system controlelements. The distal deployment system interface is adapted to expandradially during application of a proximally directed force on the distalend of the anchor when opposed by a distally directed force applied tothe proximal end of the anchor, e.g., by the anchor actuation elements106.

In some embodiments, actuating foreshortening of the apparatus involvesapplying a proximally directed force on a deployment system interface atthe distal end of the anchor, while maintaining the proximal end of theanchor in the same location. In other embodiments, foreshortening of theapparatus involves applying a distally directed force on proximal end ofthe anchor (e.g., by applying a distally directed force on the anchoractuation elements).

Anchor actuation elements 106 (e.g., fingers, tubes, posts, and controlwires connecting to posts) are preferably adapted to expand radially asthe anchor expands radially and to contract radially as the anchorcontracts radially. Furthermore, proximally or distally directed forcesby the anchor actuation elements on one end of the anchor do notdiametrically constrain the opposite end of the anchor. In addition,when a proximally or distally directed force is applied on the anchor bythe anchor actuation elements, it is preferably applied without passingany portion of a deployment system through a center opening of thereplacement valve. This arrangement enables the replacement valve tooperate during deployment and before removal of the deployment system.

The distal deployment system interface may include control wires thatare controlled, e.g., by control knob 122 of control handle 120.Similarly, the proximal regions of anchor 30 may be pushed distally viaa proximal deployment system interface at the proximal end of theanchor. The proximal deployment system interface is adapted to permitthe deployment system to apply a distally directed force to the proximalend of anchor 30 through, e.g., anchor actuation elements 106, which arecontrolled by, e.g., control knob 124 of control handle 120. Theproximal deployment system interface may be further adapted to expandradially during application of a distally directed force on the proximalend of the anchor. Such active expansion of the anchor optionally may beassisted via inflation of a balloon catheter (not shown) reversiblydisposed within apparatus 10, as described in U.S. patent applicationSer. No. 10/746,280.

Once anchor 30 is fully deployed, posts 32 and buckles 34 of anchor 30may be used to lock and maintain the anchor in the deployedconfiguration. In one embodiment, the control wires attached to posts 32are threaded through buckles 34 so that the proximally directed forceexerted on posts 32 by the control wires during deployment pulls theproximal locking end of posts 32 toward and through buckles 34. Suchlock optionally may be selectively reversible to allow for repositioningand/or retrieval of apparatus 10 during or post-deployment. Apparatus 10may be repositioned or retrieved from the patient until the two-partlocking mechanism of posts 32 and buckles 34 of anchor 30 have beenactuated. When the lock is selectively reversible, the apparatus may berepositioned and/or retrieved as desired, e.g., even after actuation ofthe two-part locking mechanism. Once again, further details of this andother anchor locking structures may be found in U.S. patent applicationSer. No. 10/746,280. Locking mechanisms used herein may also include aplurality of levels of locking wherein each level of locking results ina different amount of expansion of anchor 30. For example, the proximalend of the post can have multiple configurations for locking within thebuckle wherein each configuration results in a different amount ofanchor expansion. FIG. 2 illustrates a braided anchor of FIG. 1 in thecollapsed delivery configuration with locking elements separated.

FIG. 3 provides a detail view of a front side region of anchor braid 30with closed end turns Tu. Anchor braid 30 includes various cells, somehaving an end turn Tu. End turns can serve various functions. Forexample, end turns can be configured to reduce the sheathing force, toreduce stress within the braid during delivery and deployment, toprevent migration during expansion of the anchor, to positively registerthe anchor against the native valve during deployment. In preferredembodiments, an end turn feature functions to prevent migration and toregister the anchor by engaging the native leaflets and/or the annulusof the native valve. In preferred embodiments, the proximal region orthe distal region of anchor 30 comprises embodiments (Tu). In someembodiments, the end turn feature grasps tissue in the vicinity of thenative heart valve, such as the native valve leaflets and/or the valveannulus, e.g., by rotating into the tissue during expansion of theanchor.

FIGS. 4A-4N provide multiple examples of edge cells having an end turnfeature. The end turn features disclosed and others known in the art maybe used as engagement or grasping elements to engage and/or grasp tissuein the vicinity of a patient's heart valve, such as the native heartleaflets or the valve annulus, with the anchor. The engagement orgrasping elements may be integral with the anchor, for example, may bepart of a braided anchor. Alternatively, the engagement or graspingelements may be attached to the anchor, for example, via interweaving,crimping, welding, soldering, wire wrapping, or other suitableattachment means. The end turn features can occur at the proximal,central, or distal region of the anchor, or a combination thereof.

For example, FIG. 4A illustrates a detail view of a standard end turn Tuin an anchor braid resulting in a braid with substantially uniform cellsize and shape.

FIG. 4B illustrates a turn that has been elongated to lengthen thedistance over which forces concentrated in the turn may be distributed,resulting in an anchor braid having edge cells that are longer along theanchor axis than the other cells defined by the braid. This elongatedturn feature may be formed by routing the wire of braid about outerposts and then heat setting the wire.

FIG. 4C illustrates an alternative anchor edge cell configuration,wherein the tip of the elongated wire turn may be bent out of acylindrical shape defined by the braid of anchor braid 30. This may beachieved, for example, via a combination of routing of wire W within afixture and then heat setting. Such a turn Tu in the anchor edge cellsin FIG. 4C may reduce stress in some configurations without increasingheight, and may also provide a lip for engaging or grasping thepatient's native valve leaflets to facilitate proper positioning ofapparatus 10 during deployment.

In FIG. 4D, a W-shaped turn feature has been formed at the wire turn,e.g., by routing the wire of anchor braid 30 about a central inner postand two flanking outer posts. As with the elongated braid cells of FIGS.4B and 4C, the W-shape may better distribute stress about turn Tu.

The anchor edge cell configuration in FIG. 4E includes a loop formed inbraid 30 at the turn, which may be formed by looping wire W around aninner or outer post.

FIG. 4F provides another alternative anchor edge cell configurationhaving a figure-eight shape. Such a shape may be formed, for example, bywrapping wire W about an inner post and an aligned outer post in afigure-eight fashion, and then heat setting the wire in the resultantshape.

In FIG. 4G, the edge cells of braid 30 include a heart-shapedconfiguration, which may be formed by wrapping the wire about an alignedinner and outer post in the desired manner.

In FIG. 4H, the edge cells of braid 30 have an asymmetric loop at turnTu. The asymmetric loop will affect twisting of braid 30 duringexpansion and collapse of the braid, in addition to affecting stressconcentration.

In FIG. 4I, the anchor edge cells have a double-looped turnconfiguration, e.g. via wrapping about two adjacent inner or outerposts. Additional loops may also be employed.

The double loop turn feature may be formed with a smooth transitionbetween the loops, as in FIG. 4I, or may be heat set with a morediscontinuous shape, as in FIG. 4J.

FIG. 4K illustrates that the edge cells of braid 30 may have multipledifferent configurations about the anchor's circumference. For example,the anchor edge cells shown in FIG. 4K have extended length cells as inFIG. 4B disposed adjacent to standard size edge cells, as in FIG. 4A.

The anchor edge cells of FIG. 4L have an extended turn configurationhaving an extended loop.

The anchor edge cells shown in FIG. 4M have an alternative extendedconfiguration with a specified heat set profile.

In FIG. 4N, some or all anchor edge cells are interwoven. Wheninterwoven, one or more edge cells may be shorter or longer than anadjacent edge cell. This permits one or more edge cells to extend intoone or more leaflet pocket(s). For example, in FIG. 4N the middle Tu maybe taller than the two adjacent edge cells thus permitting the edge cellto be situated within a leaflet pocket.

In any of the embodiments herein, edge cells may be wrapped using wire,string, or sutures, at a location where the wire overlaps after an endturn as is illustrated in FIG. 4O. This tied-end turn feature preventscells from interlocking with each other during deployment.

The anchor and any of its features may be heat set at differentconfigurations. For example, the anchor may be heat set at its “at-rest”configuration such that upon unsheathing it expands radially. The endturn features/leaflet engagement elements may be heat set at a different“at-rest” configuration than the rest of the anchor. In someembodiments, the end turn features are heat set to “flower” and then“evert” upon unsheathing. In other embodiments, the end turns are heatset in an everted configuration and lie parallel/radially concentricwith the anchor, e.g., lie substantially flat against the anchor, in thesheathed delivery configuration and then to expand outward uponunsheathing. When used as grasping elements, the end turns may rotaterelative to the anchor during active expansion of the anchor in order tograsp tissue in the vicinity of the patient's heart valve.

The end turn features of FIG. 4 are provided only for the sake ofillustration and should in no way be construed as limiting. Additionalturn features within the scope of the present invention will apparent tothose of skill in the art in view of FIG. 4. Furthermore, combinationsof any such end turn features may be provided to achieve the desiredcharacteristics of anchor 30.

Referring now to FIGS. 5A-E, additional configurations for reducingstress concentration and/or circumferential stiffness of an anchor braidand/or engagement/grasping elements are illustrated. Such configurationscan be used independently or in conjunction with other configurationsdisclosed herein. Such configurations are preferably used at theanchor's edges to locally reduce the cross-sectional area ofsubstantially all cells or of substantially all cells in the anchorbraid's edge (e.g., proximal and/or distal). As seen in FIGS. 5A and 5B,turns Tu in wire W typically may have a substantially continuous (e.g.,round) cross-sectional profile. As seen in FIG. 5C, modifying the edgecell configuration by locally reducing the thickness or cross-sectionalarea of wire W at turn(s) Tu will reduce stress concentration within thewire at the turns and facilitate collapse and/or expansion of anchorbraid 30 from the delivery to the deployed configurations. Furthermore,it is expected that such localized reduction in thickness orcross-sectional area will reduce a risk of kinking, fatigue or otherfailure at turns Tu.

In any of the embodiments herein, localized reduction of an anchor wiremay be achieved via a localized etching and/or electropolishing process.Alternatively or additionally, localized grinding of the turns may beutilized. Additional processing techniques will be apparent to those ofskill in the art. As seen in FIGS. 5D-5E, wire W may, for example,comprise an oval or rectangular cross-sectional profile, respectively,after localized reduction. The wire alternatively may comprise a roundprofile of reduced cross-sectional area (not shown). Additional profileswill be apparent. Localized reduction can take place at any time (e.g.,before or after a braid is woven). Preferably, localized reductionoccurs after weaving. However, in some embodiments, a wire of a givenlength may be etched or ground at preset segments and subsequentlywoven.

With reference now to FIGS. 6A-F, a method of endovascularly replacing apatient's diseased aortic valve is provided. The method involvesendovascularly delivering an anchor/valve apparatus and properlypositioning such apparatus via positive registration with the patient'snative valve leaflets. Registration with the native valve leaflet occursusing at least one leaflet engagement element.

In FIG. 6A, modified delivery system 100′ delivers apparatus 10 todiseased aortic valve AV within sheath 110. Apparatus 10 is delivered ina collapsed delivery configuration within lumen 112 of the sheath.

As seen in FIGS. 6B and 6C, apparatus 10 is deployed from lumen 112 ofsheath 110, for example, under fluoroscopic guidance. Sheath 110includes at its distal end leaflet engagement elements 120. Upondeployment, anchor 30 of apparatus 10 dynamically self-expands to apartially deployed or at-rest configuration. This causes the anchoractuation elements, illustratively tubes 60, to also dynamically expand,as well as membrane filter (or braid) 61A and leaflet engagementelements 120. As when deployed via delivery system 100, deployment ofapparatus 10 via delivery system 100′ is fully reversible until locks 40have been actuated.

Leaflet engagement elements 120 preferably self-expand along with anchor30. In preferred embodiments, the distal ends of leaflet engagementelements 120 expand a greater radial distance than anchor 30. Moreover,engagement elements 120 may be disposed between tubes 60 of deliverysystem 100′ and a proximal region of anchor 30. However, leafletengagement elements 120 may also be disposed, e.g., attached or coupled,on the proximal region of the anchor (as is illustrated in FIG. 7). InFIG. 6, leaflet engagement elements 120 releasably engage the anchor. Asseen in FIG. 6C, the leaflet engagement elements 120 are initiallydeployed proximal of the patient's native valve leaflets L. Apparatus 10and elements 120 then may be advanced, i.e., dynamically repositioned,until engagement elements positively register against the leaflets,thereby ensuring proper positioning of apparatus 10. The leafletengagement elements engage with the proximal edges of the native valveleaflets and/or with the commissural attachments. The leaflet engagementelements need not extend all the way to the distal edge of the nativeleaflets (the leaflet pockets). In preferred embodiments, a leafletengagement element length is less than about 20 mm, more preferably lessthan about 15 mm, or more preferably less than about 10 mm. Once leafletengagement elements 120 are registered against the native valve leafletsand/or commissural attachments, apparatus 10 deploys substantiallydistal to the coronary ostia of the heart.

In any of the embodiments herein, the delivery system optionally caninclude filter structure 61A (e.g., a filter membrane or braid) as partof the anchor actuation elements, such as push tubes 60, to act as anembolic protection element. Emboli can be generated during manipulationand placement of an anchor from either diseased native leaflet(s) orsurrounding aortic tissue, and can cause blockage. Arrows 61B in FIG. 6Eshow blood flow through filter structure 61A where blood is allowed toflow, but emboli are trapped in the delivery system and removed with itat the end of the procedure.

Active expansion, e.g., foreshortening, may be imposed upon anchor 30while elements 120 are disposed proximal of the leaflets, as isillustrated in FIG. 6D. Active foreshortening can be accomplished byactuating distal anchor actuation elements (e.g., wires 50) and/orproximal anchor actuation elements (e.g., tubes 60). Upon positiveregistration of elements 120 against leaflets L, elements 120 precludefurther distal migration of apparatus 10 during additionalforeshortening, thereby reducing a risk of improperly positioning theapparatus. FIG. 6E details engagement of elements 120 against the nativeleaflets.

As seen in FIG. 6F, once apparatus 10 is fully deployed, anchor 30 maybe locked (reversibly or irreversibly) via lock 40. Subsequently,structure 61A, leaflet engagement elements 120, wires 50 and/or tubes 60may be decoupled from the apparatus, and delivery system 100′ may beremoved from the patient, thereby completing the procedure.

FIG. 7 illustrates an alternative embodiment of the apparatus of FIGS.6A-F described above, wherein leaflet engagement elements 120 arecoupled to anchor 30 of apparatus 10′ rather than to delivery system100. In the embodiment illustrated in FIG. 7, leaflet engagementelements 120 remain implanted near the patient's native heart valveafter the deployment of apparatus 10′ and removal of delivery system100. Leaflets L may be sandwiched between the proximal region of anchor30 and leaflet engagement elements 120 in the fully deployedconfiguration. In this manner, elements 120 positively registerapparatus 10′ relative to the leaflets L and preclude distal migrationof the apparatus over time.

FIGS. 8A-8C illustrate another embodiment for endovascularly deliveringan apparatus of the present invention. In FIG. 8A, a catheter 600 isdelivered percutaneously in a retrograde fashion to the aortic valve.The catheter passes through the native aortic valve before an operatoractuates the unsheathing of the anchor/valve apparatus. As the sheathingcatheter is pulled proximally out of the native valve, anchor 30 andreplacement valve 20 become unsheathed Immediately the portion of theunsheathed anchor 30 dynamically self-expands to its “at-rest” position,and replacement valve 20 within the anchor regains an uncollapsedstructure, allowing it to begin to function. In preferred embodiments inits “at-rest” position, anchor 30 presses against the native leafletslimiting blood from flowing in between the anchor and leaflet. Also, inpreferred embodiments, anchor 30 portions relatively adjacent to thevalve are externally covered by a seal 62, more preferably the entireexterior contour of anchor 30 excluding the leaflet engagement elementsis externally covered by a seal, or more preferably the entire contourof anchor 30 including the external face of the leaflet engagementelements is externally covered by a seal. A seal can be composed of anymaterial that prevents or limits the flow of blood through the anchor.In preferred embodiments, a seal is composed of a thin, elastic polymeror any other type of fabric. The seal can be attached to the anchor and,in some embodiments, to the distal end of the valve, by any means knownin the art. In preferred embodiments, a seal is attached to the anchorby suturing.

In FIG. 8B, as the catheter is further pulled proximally, the proximalend of anchor 30 and anchor actuation elements or fingers 50 areunsheathed. In this embodiment, it is possible to visualize that theseal covers the entire contour of the anchor including the external faceof the leaflet engagement element(s) 70. As soon as the proximal end ofthe anchor is exposed, it also dynamically expands. Furthermore, whenfingers 50 become exposed, replacement valve 20 begins to function,permitting blood to flow through replacement valve 20, between fingers50 and around the catheter 600. This also permits blood to flow into thecoronary ostias. In other embodiments where the seal does not cover theproximal end of the anchor, the replacement valve can begin to functionas soon as the unsealed portion of the anchor is unsheathed. This causesthe leaflet engagement element(s) 70 to radially expand to their heatset position and engage with the native heart leaflets.

Next, as seen in FIG. 8C, as the apparatus is actively foreshortenedusing proximal actuators (e.g., fingers) and/or distal actuators (e.g.,wires 55), the leaflet engagement elements positively register with thenative valve leaflets. Foreshortening can cause seal 62 to bunch up andcreate pleats. These pleats can then fill pockets, thereby improving theparavalvular seal. In embodiments in which the leaflet engagementelements are covered with a seal, at least a portion of the seal is alsopositioned between the native valve leaflets and the aortic wall. Oncethe anchor is fully compressed within the aortic valve, the anchor islocked, the proximal and distal actuators are disengaged, and the sealis adapted to further limit blood flow around the replacement valve. Thecatheter is subsequently withdrawn, leaving behind valve 20, seal 62 andanchor 70. When fully deployed, the anchor is substantially distal tothe coronary ostia of the patient, such that it will not interfere withblood flow through the ostia.

FIGS. 9A-9B illustrate an embodiment wherein only a distal portion ofanchor 30 is covered by seal 62, and wherein anchor 30 is only partiallydeployed since the blood can escape through the proximal end of theanchor braid. As anchor 30 in this embodiment is unsheathed, it pressesagainst the native valve leaflets. At this point replacement valve 20 isfunctional even though anchor 30 is not fully deployed, since blood canescape through the proximal end of the anchor braid. This allows bloodto flow through replacement valve 20 and out of holes in the distal endof anchor 30 during systole (FIG. 9A) while preventing backflow duringdiastole (FIG. 9B).

FIGS. 10A-10B illustrate a similar embodiment wherein seal 62 aroundanchor 30 surrounds the entire contour of anchor 30. In this embodiment,valve 20 does not become functional until both anchor 30 and a portionof fingers 50 are unsheathed. As soon as a portion of fingers 50 isunsheathed, replacement valve 20 is fully functional. This allows bloodto flow through replacement valve 20 and anchor 30, out of fingers 50,and around catheter 600 into the aorta and coronary ostias duringsystole. Similarly, during diastole, replacement valve 20 closespreventing blood backflow from entering the chamber.

In any of the embodiments herein the anchor is preferably aself-expanding anchor braid. Anchor braids of the present invention canbe made from one or more wires, more preferably 2-20 wires, morepreferably 3-15 wires, or more preferably 4-10 wires. Moreover, thedensity of the braid can be modified by various forms of weave used.

FIGS. 11A-11D illustrate various anchor braid embodiments contemplatedby the present invention.

FIG. 11A illustrates two groups of cells or two braids interwoven in thecenter. The top group of cells forms a more open weave than the bottomgroup of cells, which forms a denser weave.

FIG. 11B illustrates another embodiment of an anchor braid having threegroups of cells. The top and bottom (proximal and distal) edges of theanchor braid have denser cells than the central portion of the anchor.Also, the edges of the anchor are woven from a thinner filament than thecentral portion.

In another embodiment illustrated by FIG. 11C, all three sections of ananchor valve are woven by more than one wire. The wires of each sectionare made of a different material and/or thickness. Wires at thesectional boundaries may or may not interconnect with wires from adifferent section. Each of the sections of the braid anchor may becomposed of a different number of wires.

FIG. 11D illustrates another embodiment of a braided anchor having threesections. In this embodiment, all sections are composed of a singlewire. The proximal and distal sections/edges of the braided anchor havethe same pitch. The central region of the braided anchor has a differentpitch than the edge sections.

FIGS. 12A-12E illustrate side views of braided anchors having more thanone braid pitch. Varying pitch within the anchor allows localizedvariations in foreshortening across the anchor, as greaterforeshortening is achieved by higher pitch of the braid. Moreover, thelocalized foreshortening features allow for the design of a braid whichincorporates various diameters depending upon the amount offoreshortening. (The greater the foreshortening, the greater thediameter increase upon deployment.)

FIG. 12A, is a side view representation of the braided anchor of FIG.11D. On the left side of the figure, the expanded anchor is illustratedhaving a denser weave (shorter pitch) at the distal and proximal ends;hence the dots are located closer to each other. The middle section ofthe anchor is composed of a looser weave that is generated by a higherpitch braid and is represented by dots that are farther away from eachother. On the right side of the figure, the braided anchor isforeshortened and the dots are collapsed closer to each other. In thiscase, the central portion of the anchor foreshortened more than theproximal and distal edges.

FIG. 12B illustrates a side view of a foreshortened braided anchor thatis created by low pitch at the edges and high pitch in the middle.

FIG. 12C illustrates a side view of a foreshortened braided anchor thatis created by high pitch edges and low pitch middle section.

FIG. 12D illustrates a side view of a foreshortened braided anchor thatincludes a sealing feature or space filling feature at both ends. Thistype of anchor can be created by a high pitch braid at edges, low pitchbraid in the middle and heat setting the edges to curl upon unsheathing.These end features can be useful in facilitating anchoring byfunctioning as a locator and/or sealing. In one embodiment, the curledends of the anchor in FIG. 12D can be used as tissue engagementelements.

FIG. 12E illustrates a side view of a foreshortened braided anchor thatis associated with an everting valve or locational/engagement/graspingfeatures. In preferred embodiments, the middle section of the anchor maybe composed of thicker wire(s) than edge section(s). For example, aneverting feature at the proximal end can function as a leafletengagement element as disclosed herein.

FIGS. 13A-13E illustrate an example of the process of deploying ananchor, such as the one illustrated in FIG. 12B above.

FIG. 13A illustrates a braided anchor 30 in its expanded or elongatedconfiguration. The anchor is composed of three sections. The distal andproximal sections of the anchor are made of a fine weave, low pitchbraid and the middle section of the anchor is made of a thicker threadand higher pitch braid. The distal and proximal section are preferablyheat set to roll upon unsheathing, though some rolling may occur simplyfrom active foreshortening of the fine weave braid. In preferredembodiments, the filaments of the fine weave braid are less than 0.01cm, or more preferably less than 0.005 cm in thickness. On the otherhand, thicker filaments of the middle section are preferably 0.01 cm orgreater in thickness or more preferably 0.015 cm or greater inthickness. Posts 32 are coupled to the middle section of the anchor. Fordeployment, tubes (or fingers) 106 are coupled to the anchor's middlesection.

FIG. 13B illustrates an anchor during the process of deployment afterthe anchor is unsheathed. The anchor is pushed distally by tubes andpulled proximally by wires and begins foreshortening. In someembodiments, the distal section rolls up and can act as a locator,assisting the operator in locating the aortic valve or engaging thevalve annulus, or as a seal preventing leakage. In some embodiments, theproximal section may roll down and be used as a leaflet engagementelement to prevent distal migration or as a proximal seal.

In FIG. 13C, the device may be configured such that the middle sectionof the valve may form an hour glass shape or a round shape. The tubesmay subsequently be removed as described before.

FIG. 13D is another illustration of the braided anchor in its elongatedconfiguration.

FIG. 13E is another illustration of the braided anchor in itsforeshortened configuration.

FIGS. 14A-14C illustrate the process of forming a pleated seal around areplacement valve to prevent leakage. FIG. 14A illustrates a fabric seal380 prior to deployment and foreshortening of the anchor/valveapparatus. In FIG. 14A, the fabric seal 380 extends from the distal endof valve 20 proximally over anchor 30 during delivery. Duringdeployment, as illustrated in FIG. 14B, anchor 30 foreshortens, and thefabric seal 380 bunches up to create fabric flaps and pockets thatextend into spaces formed by the native valve leaflets 382. The bunchedup fabric or pleats occur, in particular, when the pockets are filledwith blood in response to backflow blood pressure. The pleating cancreate a seal around the replacement valve. FIG. 14C illustrates anchor30, surrounded by fabric seal 380 in between native valve leaflets 382.In preferred embodiments, at least a portion of a seal is capturedbetween the leaflets and the wall of the heart when the anchor is fullydeployed

Referring now to FIGS. 15 and 16, a replacement heart valve and anchorhaving engagement elements configured to grasp tissue in the vicinity ofa patient's heart valve is described. The grasping engagement elementsare configured to rotate about the anchor during active expansion of theanchor. Such rotation may be used to grasp the tissue, e.g., to graspleaflets of the patient's native heart valve. The grasping elementspreferably grasp tissue atraumatically.

Anchor 30 comprises grasping elements 80. The grasping elements maycomprise, for example, heat-set end turns Tu of a braid from which theanchor is fabricated, a special weave of the braid, or multiple wiresattached to one another by crimping, welding or other means. Thegrasping elements may be integral with anchor 30 or may be attached tothe anchor, for example, via interweaving, crimping, welding, soldering,wire wrapping, or other suitable attachment means. Grasping elements 80may have a different cross-sectional profile than that of the materialfrom which the body of anchor 30 is fabricated, e.g., from that of thewires forming the braid of anchor 30. Additionally or alternatively, thegrasping elements may be fabricated of different materials than thosefrom which the anchor is fabricated and/or from which other graspingelements are fabricated.

In FIG. 15, grasping elements 80 illustratively extend from a proximalregion of the anchor, e.g., for atraumatic grasping of tissue of thepatient's native valve leaflets. Such grasping of the valve leaflets mayfacilitate proper positioning of the anchor distal of the coronaryostia, and also might resist distal movement of the anchor. Graspingelements may additionally or alternatively extend from a distal regionof the anchor, e.g., for atraumatic grasping of the annulus of thepatient's heart valve. Such grasping of the annulus may facilitatepositioning proximal of the mitral apparatus, and also might resistproximal movement of the anchor.

Anchor 30 comprises a self-expanding anchor having a deliveryconfiguration, as seen in FIG. 15A; an at-rest configuration, as seen inFIG. 15B; and a deployed configuration, as seen in FIG. 15D. The anchormay, for example, self-expand from the delivery configuration to theat-rest configuration after deployment from a delivery sheath. Theanchor then may be actively expanded, e.g., foreshortened, to thedeployed configuration of FIG. 15D, in which configuration it may, forexample, be locked using, e.g., one of the lock mechanisms describedabove. FIG. 15C illustrates the anchor during active expansion andduring transition from the at-rest configuration to the deployedconfiguration. Grasping elements 80 may move radially relative to oneanother during expansion of the anchor. For example, in FIG. 15, thegrasping elements move radially apart during self-expansion of theanchor to the at-rest configuration, then move radially closer togetherduring active expansion to the deployed configuration.

As seen in FIG. 15A, grasping elements 80 are positioned substantiallyparallel with anchor 30 in the delivery configuration, e.g., thegrasping elements lie substantially flat against the anchor duringdelivery. The grasping elements may be constrained to lie flat by anexterior constraint, such as the delivery sheath. As seen in FIG. 15B,grasping elements 80 form a first angle .alpha. with the anchor in theat-rest configuration. As seen in FIG. 15C, as the anchor expands to thedeployed configuration, the grasping elements 80 rotate about anchor 30,such that the angle .alpha. changes. In the fully deployed configurationof FIG. 15D, the grasping elements form a second angle .beta. with theanchor. If a lock is provided with the anchor, locking the anchor in itsdeployed configuration helps maintain the anchor's grasp of the tissue.

The first angle .alpha. illustratively is larger than the second angle.beta., such that the grasping elements rotate inward toward the body ofanchor 30 during active anchor expansion from the at-rest configurationto the deployed configuration. The grasping elements may grasp tissue,such as the patient's valve leaflets, between the body of the anchor andthe grasping elements during such rotation of the grasping elements. Asseen in FIG. 15D, the second angle 13 may, for example, approximate zerowhen no tissue is grasped or captured between the grasping element andthe anchor. In alternative embodiments of grasping elements 80, thesecond angle .beta. may be larger than the first angle .alpha., suchthat the grasping elements rotate outward and away from the body of theanchor for grasping tissue during active anchor expansion. In stillfurther alternative embodiments, the second angle .beta. may besubstantially equal to the first angle .alpha., such that the graspingelements do not rotate, or rotate only minimally, during activeexpansion of the anchor.

FIG. 16 shows anchor 30 and replacement valve 20 deployed across apatient's native valve. Grasping elements 80 rotate inward towards thebody of anchor 30 during expansion of the anchor, thereby graspingleaflets L of the patient's aortic valve and pulling the leaflets towardthe anchor, e.g., during diastole. This grasping of the leaflets securesthe apparatus against the native valve, thereby resisting distalmigration of the apparatus and/or leakage. Furthermore, graspingelements 80 ensure that apparatus 10 is disposed distal of coronaryostia O and extends distal of the leaflets to valve annulus A.

With reference now to FIG. 17, anchor 30 may comprise any of a varietyof grasping elements 80. In FIG. 17A, the anchor illustrativelycomprises five separate grasping elements to grasp the leaflets aroundthe entire circumference of the valve. The anchor may, for example,comprise 3-6 grasping elements for grasping the leaflets. Alternatively,the anchor may comprise more than six grasping elements, as in FIG. 17B.Providing additional grasping elements may facilitate grasping of thecommissures of the leaflets. Furthermore, providing multiple graspingelements may distribute forces applied to the tissue amongst thegrasping elements, thereby reducing a risk of misalignment of the anchorand/or replacement valve. As with the earlier embodiments, thisembodiment may also be provided with a lock mechanism to maintainexpansion of the anchor and grasping of the tissue.

With reference to FIG. 18, in addition to altering the number ofgrasping elements, the location and/or orientation of the graspingelements also may be altered. FIG. 18 show variations of anchor 30 inthe deployed (and possibly locked) configuration. In FIG. 18A, theanchor comprises two circumferential sets of grasping elements 80 spacedfrom one another along the length of the anchor. In one variationdescribed hereinbelow with respect to FIG. 19, the grasping elements ofFIG. 18A provide an outwardly-directed force such that the proximal setof grasping elements may, for example, grasp wall tissue, while the moredistal set may grasp the interior of the patient's valve leaflets andpress the leaflets against the wall.

In FIG. 18B, the grasping elements extend from the distal region ofanchor 30, for example, to grasp the annulus of the patient's valve. InFIG. 18C, the anchor comprises a circumferential set of graspingelements that extend from the proximal region of the anchor for graspingthe patient's valve leaflets, as well as a circumferential set of thegrasping elements that extend from the distal region of the anchor forgrasping the patient's valve annulus. The proximal grasping elements areoriented distally to facilitate grasping of the leaflets, while thedistal grasping elements are oriented proximally to facilitate graspingof the annulus.

Referring now to FIG. 19, a variation of the grasping elements of FIG.18A that can accommodate enlargement in a patient's native valvestructures over time is described. In FIG. 19, grasping elements 80apply an outwardly-directed force when anchor 30 is deployed. Anchor 30may be deployed such that grasping elements 80 grasp tissue in thevicinity of the patient's heart valve, for example, such that theproximal grasping elements grasp wall tissue and the more distalelements grasp the interior of the valve leaflets and press them againstthe wall. Over time, the patient's native valve structures may expand.If the anchor is locked in the expanded configuration, it may be unableto further expand with the native structures. As seen in FIG. 19B, sincethe grasping elements apply an outwardly-directed force, they rotateoutward relative to the anchor as the native structures expand, therebyaccommodating such expansion and reducing a risk of migration of theanchor or blood leakage around the anchor.

FIG. 20 show deployment and resheathing of apparatus 10 comprisinggrasping elements 80. As seen in FIG. 20A, apparatus 10 havingreplacement valve 20 and anchor 30 with grasping elements 80 ispositioned in the delivery configuration within sheath 110 of deliverysystem 100. Grasping elements 80 are positioned substantially parallelto, and/or lie flat against, anchor 30.

In FIG. 20B, as the sheath is retracted relative to apparatus 10, theanchor and grasping elements begin to dynamically self-expand. Thegrasping elements positioned along the proximal region of the anchormove laterally apart from the grasping elements positioned along thecentral region of the anchor as the anchor self-expands. In FIG. 20C,once the sheath has been fully retracted, the anchor assumes the at-restconfiguration with the grasping elements 80 forming a first angle.alpha. with the body of the anchor. It should be understood that eachgrasping element 80 may form its own, potentially distinct, angle withthe anchor.

Anchor actuation elements 106 then may be used in conjunction withdistal control wires and other elements of delivery system 100 toactively expand the anchor (and optionally lock the anchor), asdescribed previously. Grasping elements 80 rotate relative to anchor 30during active expansion of the anchor and form a second angle .beta.with the anchor in the fully deployed configuration of FIG. 20D. As withthe first angle .alpha., each grasping element 80 may form its own,potentially distinct, second angle .beta. with the anchor. The secondangle(s) .beta. may be larger or smaller than the first angle(s).alpha., i.e., the grasping elements may rotate outward or inwardrelative to the anchor. In some embodiments, the second angle(s) .beta.may be substantially equal to the first angle(s) .alpha., i.e., thegrasping elements may not rotate, or may rotate only minimally, duringactive expansion of the anchor. In FIG. 20, the grasping elements rotateinward and the proximal grasping elements move laterally closer to themore distal grasping elements during active expansion.

FIG. 20E illustrates that the anchor may be resheathed, e.g., withinsheath 110, after deployment of the anchor. The grasping elements againlie substantially flat against the anchor during resheathing. Theapparatus may be repositioned or retrieved via resheathing.

Referring now to FIG. 21, a seal for use with grasping elements 80 isdescribed. Seal 90 of FIG. 21 only covers the grasping elements 80, suchthat the seal does not interfere with the primary anchoring function ofanchor 30. Seal 90 illustratively covers all grasping elements 80, butalternatively may cover only a subset of the grasping elements.Furthermore, the seal may be utilized regardless of the positioning,orientation or quantity of the grasping elements. The seal may becaptured between leaflets of the patient's heart valve and a wall of thepatient's heart when the anchor and replacement valve are fullydeployed. The seal may be adapted to reduce or prevent blood flow aroundthe replacement valve when the anchor and replacement valve are fullydeployed.

FIG. 22 illustrates an alternative embodiment of the grasping elementsand seals of FIG. 21. In FIG. 22, anchor 30 comprises both proximalgrasping elements 80 for grasping valve leaflets and distal graspingelements 80 for grasping the annulus of the patient's valve. Seal 90illustratively is positioned only over the distal grasping elements,such that the seal is captured against an annulus of the patient's heartvalve in the deployed configuration. The seal forms a distal ‘skirt’that reduces or prevents blood flow around the replacement valve whenthe anchor and the replacement valve are fully deployed.

FIG. 23 illustrates another alternative embodiment wherein seal 90covers both the proximal and distal grasping elements and extendsbetween the elements. The seal forms a tubular seal structure exteriorto the body or braid of anchor 30 which can conform and seal againstparavalvular leaks. FIG. 24 illustrates seal 90 of FIG. 23 deployedacross a patient's native valve. The proximal grasping elements graspthe valve leaflets L and resist distal migration, while the distalgrasping elements grasp the valve annulus A and resist proximalmigration. Tissue grasping with grasping elements 80 preferably isatraumatic. As seen in FIG. 24, apparatus 10 is positioned distal ofcoronary ostia O, and seal 90 prevents or reduces blood flow around thereplacement valve apparatus.

FIG. 25 is an embodiment of apparatus 10 comprising grasping elements 80that are attached to anchor 30, rather than being formed integrally withthe anchor, is described. In FIG. 25, grasping elements 80 comprisewires 82, as well as wire crimps 84 that attach the wires to the anchor.Each grasping element 80 comprises a wire 82 that optionally may beinterwoven with the braid of anchor 30. Each end of each wire 82 isattached to the braid of anchor 30 via a crimp 84. The spacing about thecircumference of the anchor between the ends of each wire forms anatraumatic grasping element 80. A plurality of such grasping elementsare formed about the circumference of the anchor to facilitatecircumferential grasping of tissue.

In FIG. 25, grasping elements 80 are attached to anchor 30 in a mannersuch that adjacent grasping elements partially overlap one another. Thedegree of overlap may be varied, as desired. Alternatively, the graspingelements may be attached such that there is no overlap between adjacentgrasping elements.

Each crimp 84 of FIG. 25 has a first end that crimps to a wire 82 and asecond end that crimps to the braid of anchor 30. In this configuration,each grasping element requires two unique crimps 84 for attachment tothe braid. With reference to FIG. 26, an alternative crimp 85 forattaching the grasping elements to the anchor is described that reducesthe total number of crimps required to attach a given number of graspingelements 80 to anchor 30. Each crimp 85 comprises a central section 86that crimps onto the anchor, a first end 87 a that crimps onto a firstwire 82 and a second end that crimps onto a second wire 82. Thus, crimps85 are shared between adjacent grasping elements 80, thereby reducingthe number of crimps needed to attach the grasping elements. In FIG. 26,adjacent grasping elements illustratively do not overlap, but it shouldbe understood that overlapping grasping elements alternatively may beprovided, as in FIG. 25.

In any of the embodiments of engagement or grasping elements describedherein, the elements may have a different cross-sectional profile thanthat of the material from which the body of the anchor is fabricated,e.g., from that of the wires forming the braid of anchor 30.Additionally or alternatively, the grasping elements may be fabricatedof different materials than those from which the anchor is fabricatedand/or from which other grasping elements are fabricated. In FIG. 26,wires 82 forming grasping elements 80 illustratively have largercross-sectional diameters than the cross-sectional diameter of thewire(s) forming the braid of anchor 30. This may, for example, make thewires forming grasping elements 80 stiffer than the wire(s) forming thebraid of anchor 30.

Referring now to FIG. 27, alternative attached grasping elements 88 aredescribed. Each grasping element 88 is only attached to anchor 30 at asingle location. Each grasping element 88 comprises a wire 82 that isformed into a loop. The two ends of the loop are crimped within a firstend of a crimp 84. The other end of the crimp is crimped onto theanchor. By forming each wire 82 into a loop, an atraumatic graspingelement 88 is formed for tissue grasping without necessitatingattachment of the grasping element to the anchor at multiple locationsabout the circumference of the anchor.

Although the grasping elements of FIGS. 25-27 have been attached toanchor 30 via crimping, it should be understood that any alternative oradditional attachment technique may be utilized. For example, thegrasping elements may additionally or alternatively be attached viainterweaving with the braid and/or via welding soldering, wire wrapping,or other suitable attachment means. Additional attachment techniqueswithin the scope of the present invention will be apparent to those ofskill in the art.

In any of the embodiments described herein, the engagement or graspingelements or the step of engaging/grasping the tissue may provide alocating function for properly placing the apparatus. This locatingfunction may be accomplished without necessitating a precise placementof the replacement valve, especially in embodiments that comprise bothproximal and distal grasping elements, e.g., that grasp both the valveleaflets and the valve annulus. This locating function advantageouslymay be accomplished without necessitating tactile feedback regarding thepositioning of the replacement valve.

While preferred embodiments of the present invention are shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A method for endovascularly replacing a patient'snative heart valve, the method comprising: delivering a radiallyexpandable anchor and a replacement valve supported within the anchor toa vicinity of the native heart valve, wherein the anchor defines aplurality of cells having a tubular shape extending from a downstreamend of the plurality of cells to an upstream end of the plurality ofcells, the anchor including leaflet engagement elements attached at thedownstream end of the plurality of cells and extending distallytherefrom; sandwiching native valve leaflets between the distallyextending leaflet engagement elements and the plurality of cells; andradially expanding the anchor to a fully deployed configuration tosecure the anchor within the native heart valve; wherein the replacementvalve allows the flow of blood downstream through the replacement valvein a first configuration and prevents the flow of blood through thereplacement valve in a second configuration.
 2. The method of claim 1,wherein the native valve leaflets are sandwiched between a downstreamregion of the plurality of cells and the leaflet engagement elements inthe fully deployed configuration.
 3. The method of claim 1, wherein theleaflet engagement elements are formed from arcuate wires attached tothe plurality of cells at opposing ends of the arcuate wires.
 4. Themethod of claim 3, wherein the opposing ends of the arcuate wires arecircumferentially spaced apart around the plurality of cells.
 5. Themethod of claim 1, wherein adjacent leaflet engagement elements are freefrom circumferential overlap with each other.
 6. The method of claim 1,wherein adjacent leaflet engagement elements partially circumferentiallyoverlap each other.
 7. The method of claim 1, wherein the anchor furtherincludes a seal extending downstream over the plurality of cells fromthe upstream end of the plurality of cells.
 8. The method of claim 1,wherein the anchor is self-expandable from a delivery configuration toan at-rest configuration.
 9. The method of claim 8, wherein the anchorrequires active foreshortening to shift from the at-rest configurationto the fully deployed configuration.
 10. A method for endovascularlyreplacing a patient's native heart valve, the method comprising:delivering a radially expandable anchor and a replacement heart valvesupported within the anchor to a vicinity of the native heart valve;wherein the anchor defines a tubular structure extending from adownstream end to an upstream end, the anchor including leafletengagement elements attached at the downstream end of the tubularstructure and extending distally therefrom; deploying the leafletengagement elements adjacent native valve leaflets, downstream of thenative valve leaflets; advancing the anchor and leaflet engagementelements upstream to sandwich the native valve leaflets between theleaflet engagement elements and an outer surface of the tubularstructure downstream of an annulus of the native heart valve; andradially expanding the anchor to a fully deployed configuration tosecure the anchor within the native heart valve; wherein the replacementheart valve allows the flow of blood downstream through the replacementheart valve in a first configuration and prevents the flow of bloodthrough the replacement heart valve in a second configuration.
 11. Themethod of claim 10, wherein the native valve leaflets are sandwichedagainst the outer surface of the tubular structure in the fully deployedconfiguration.
 12. The method of claim 10, wherein the leafletengagement elements are formed from arcuate wires having a first enddirectly attached to the tubular structure at the downstream end and asecond opposing end directly attached to the tubular structure at thedownstream end.
 13. The method of claim 12, wherein the first and secondends of the arcuate wires are circumferentially spaced apart around thedownstream end of the tubular structure.
 14. The method of claim 10,wherein adjacent leaflet engagement elements are free fromcircumferential overlap with each other.
 15. The method of claim 10,wherein adjacent leaflet engagement elements partially circumferentiallyoverlap each other.
 16. The method of claim 10, wherein the anchorfurther includes a seal extending downstream over the tubular structurefrom the upstream end of the tubular structure.
 17. The method of claim10, wherein the anchor is self-expandable from a delivery configurationto an at-rest configuration.
 18. The method of claim 17, wherein theanchor requires active foreshortening to shift from the at-restconfiguration to the fully deployed configuration.